Cytogenetic investigations on mice treated with lead

Dietary lead at different dose levels was given to female C57B1 mice for periods up to 3 months. No severe chromosome or chromatid aberrations were observed at any dose level and the frequency of chromatid gaps increased significantly only at the highest doses. (0.5 and 1% of lead in the diet). The number of micronuclei in polychromatic erythrocytes also remained at control levels after lead treatment, whereas known mutagenic agent such as Myleran and Mitomycine C raised their incidence markedly. Taking into account also the data in the literature, it is concluded that lead per se probably has no mutagenic action on mammals.